Do not go upon what has been acquired by repeated hearing; nor tradition; nor rumor; nor what is in a scripture; nor surmise; nor axiom; nor specious reasoning; nor bias towards one’s beliefs; nor upon another's seeming ability; nor upon the consideration, 'The monk is our teacher.' When you yourselves know: 'These things are good; these things are not blamable; these things are praised by the wise; undertaken and observed, these things lead to benefit and happiness,' enter on and abide in them.On the other hand, every school of Buddhism includes faith. In certain circles, the merest hint that Buddhism encourages (or possibly even allows for free enquiry) or that this is the meaning of the Kalama Sutra will get shouted down usually along with reference to an interpretation of the sutra by Bikkhu Bodhi. So how should we interpret this sutra? Interpretations vary and we have to bear in mind of course that contemporary interpretations may have drifted somewhat from the original intention of the teaching(probably in the direction of faith-based dogmatism if the 'meme' theory of religious evolution has much truth to it).
Bikkhu Bodhi argues that the advice to disregard dogma, rumour, spurious logic, personal bias, the authority of one's teacher and so on, but to go upon that which can be personally verified and that which is 'praised by the wise', is directed at non-Buddhists and that once someone accepts the Buddha as one's teacher, this advice no longer applies and one should accept the authority of Buddha on faith.
...because the Kalamas had not yet come to accept the Buddha in terms of his unique mission, as the discloser of the liberating truth, it would not have been in place for him to expound to them the Dhamma unique to his own Dispensation... These teachings are specifically intended for those who have accepted the Buddha as their guide to deliverance, and in the suttas he expounds them only to those who "have gained faith in the Tathagata" and who possess the perspective necessary to grasp them and apply them....While it seems clear that the Kalama Sutra doesn't necessarily encourage dispensing with all faith in favour of personal investigation, this interpretation seems problematic.
We begin with an immediately verifiable teaching whose validity can be attested by anyone with the moral integrity to follow it through to its conclusions, namely, that the defilements cause harm and suffering both personal and social...This increased confidence in the teaching brings along a deepened faith in the Buddha as teacher, and thus disposes one to accept on trust those principles he enunciates that are relevant to the quest for awakening, even when they lie beyond one's own capacity for verification.
First of all, the logic is pretty convoluted - we are to believe that, purely as a means of teaching/indoctrinating these people, the Buddha encouraged them to believe he was in favour of independent verification, but neglected to mention that after they 'signed up' they would be increasingly encouraged to discard it in favour of faith in metaphysical doctrines which they would never be able to verify. This seems to characterise the Buddha as exactly the sort of spiritual con-artist that the Kalamas had encountered before and were trying to defend themselves against. Also, this would involve the Kalama's directly contradicting Buddha's own advice to not go solely upon the consideration, 'The monk is our teacher.' Surely such advice was not to be disregarded after the monk Siddharth Gautama became their teacher?
It is further contradicted by the next section which is often regarded as a sort of Buddhist-equivalent to Pascal's Wager. Bikkhu Bodhi himself summarises this nicely where he describes the solaces of a ... "noble disciple [i.e. a monk, a disciple of Buddha] , devoid of covetousness and ill will, undeluded" dwells pervading the world with boundless loving-kindness, compassion, appreciative joy and equanimity. Thus purified of hate and malice, he enjoys here and now four "solaces": If there is an afterlife and kammic result, then he will undergo a pleasant rebirth, while if there is none he still lives happily here and now; if evil results befall an evil-doer, then no evil will befall him, and if evil results do not befall an evil-doer, then he is purified anyway.
In other words, it doesn't matter whether followers of Buddha believe in literal rebirth and Kamma, they will benefit from the practice anyway. Sounds pretty reasonable.
Human beings are naturally empirical animals - we build up our understanding of the world by interacting with it. But we are also social animals and this is where much of our strength comes from - no individual has enough direct experiences in a lifetime to build up a really broad understanding - we rely on the experiences of others. Buddha, it seems to me, is pragmatically urging the Kalamas to rely primarily on what they can directly verify and on trusted opinion.
The Sutra certainly doesn't suggest that people can believe whatever they like, however empiricism is not believing whatever you like, it is being humble before reality. On the other hand, it doesn't, as I interpret it, imply at all that we don't need any faith at all. Without faith, we have no constancy in our practice or our mind - we need to have confidence in the teacher and in the teaching. But this is confidence that is reinforced by direct experience.
The Kalama Sutra
A Look at the Kalama Sutra - Bikkhu Bodhi
Buddhism and Science: Probing the Boundaries of Faith and Reason - Dr. Martin J. Verhoeven
How Free is Freedom of Thought - Sanath Nanayakkara